News Release

Scientists Map Ocean Floor Near Palmer Station in Antarctica

Reveal Hidden Dangers to Passing Ships

Using inflatable boats, a portable depth sounder with GPS, and a REMUS
autonomous underwater vehicle, a team of scientists and engineers has
created the first detailed, comprehensive chart of the ocean floor
around Palmer Station in Antarctica, revealing previously unknown
submerged rocks.

The new chart, the first in 50 years, was made by a research team from
the Woods Hole Oceanographic Institution (WHOI) and the University of Southern
Mississippi over five weeks in April and early May as they looked for
sites for a new underwater observatory. Their findings revealed a
number of previously unmapped submerged rocks, among them a set of
sharp rocky pinnacles that are potential navigational hazards. Some
rise nearly 100 meters (about 330 feet) to a depth of six meters (about
20 feet) below the surface and near to the routes generally taken by
ships through the area.

The previous nautical chart of the area was produced in the mid 1900's
by single soundings taken at very wide spacing. Although some
underwater hazards were marked on the earlier chart, the old chart was
found to be incorrect by at least 0.5 nautical miles (just under one
mile).

Since Palmer Station was first established as a scientific outpost in
1965, ships have followed a particular route through the visible
rocks. In typical marine navigation in poorly charted
waters, ships new to the area proceed cautiously, making continuous
soundings with their bridge fathometer. They then note their
routes on charts and follow the same routes when entering and departing
the area.

“We were astounded to find these rocks so close to the surface and the
shipping lanes,” said Scott Gallager, an associate scientist in the
Biology Department of the Woods Hole Oceanographic Institution. “When
you think of all the ship traffic that has passed through the area
through the years and the often hostile weather conditions, you realize
how skillful and lucky they have been.” Gallager and co-principal
investigator Vernon Asper of the University of Southern Mississippi
conducted the survey with WHOI engineers Keith von der Heydt and
Gregory Packard. Funding was provided by the National Science
Foundation’s Office of Polar Programs.

Palmer Station is at 64°46' S, 64°03' W, on protected Arthur Harbor on
the southwestern coast of Anvers Island, about midway down the
Antarctica Peninsula. Palmer is one of three U.S. research stations on
the continent and the only station north of the Antarctic Circle. Named
for American sealer Nathaniel B. Palmer, who in 1820 was one of the
first to see Antarctica, the station was built in 1968 to replace the
prefabricated wood huts of 'Old Palmer' station, established in 1965.
In 1990 Palmer Station was designated by the National Science
Foundation as a long term ecological research (LTER) site.

Most researchers travel to the station from Punta Arenas, Chile across the Drake Passage aboard the research vessels Laurence M. Gould and Nathaniel B. Palmer, operated by the National Science Foundation for the Antarctic research community. In light of the new information, the Gould and the Palmer are now using modified access routes into Palmer Station to give a wider berth to the newly imaged rock hazards.

Gallager, Asper and their team went to survey the sea floor around
Palmer Station to locate possible sites for the installation of the
first underwater cabled observatory in Antarctica. The Polar Remote
Interactive Marine Observatory (PRIMO) will be equipped with sensors to
monitor ocean properties during an entire year. It will be
installed in the Austral fall of 2006 about two nautical miles to the
south of Palmer Station on the ocean bottom at a depth of approximately
130 meters (425 feet), connected by a fiber-optic and electrical cable
to a newly constructed building at Palmer Station.

Instruments, including current meters, plankton imaging systems, and an
under ice video observation system, will travel up and down through the
water column throughout the day from the observatory’s base to just
below the surface, even after the pack ice forms and covers the
area. Proximity sensors on the top of the profiling platform will
send and receive acoustic signals to prevent it from contacting the
ice. The scientists hope to use this first observatory as a proof
of concept and test-bed for a similar observatory to be located in
deeper water. Other scientists, students and educators around the
world will be able to access PRIMO via the Internet and conduct
experiments related to plankton distributions, carbon cycling, and
climate change.

“Protection of the cable and underwater platform from grounding
icebergs at depths of 100 meters (330 feet) or greater is a major
concern, and the primary reason for needing the detailed underwater
maps, but finding the rocks was an unexpected bonus of the trip,” said
Gallager. “The real challenge now is to design and build a platform
that will survive the harsh Antarctic winters in the water and provide
us the first ever long-term, high resolution glimpses of what is going
on in this region of the Southern Ocean. That will be exciting!”

Originally published: June 8, 2005

WHOI is the world's leading non-profit oceanographic research organization. Our mission is to explore and understand the ocean and to educate scientists, students, decision-makers, and the public.